This invention relates to a panel inspection plug that may be operated to provide an entrance through which a user may insert an inspection probe, device or device attachment into an area requiring inspection, testing and/or sampling, and more particularly to such an inspection plug that can be adapted to fit into an opening or hole within the panel to allow access to an interior environment covered by the panel.
Inspecting a utility system, such as in the electric, gas, telephone, chemical and sewer industries, can be a difficult task. Utility workers routinely inspect, test, repair and sample the contents of underground utility systems which are designed as subsurface structures. Utility workers generally enter or gain access to these subsurface structures through an opening at the surface that is normally covered by a panel or manhole cover. Prior to entering the underground structure, the manhole cover typically must be removed and atmospheric tests performed on the interior environment to ensure that the underground structure is safe to enter, e.g., that little or no toxic substances or combustible gases are present. The inspection may be performed with air and fluid monitors utilizing probes, tubes, etc., that may be used to gather or detect unidentified matter and gasses. Most panels or manhole covers are made of solid cast iron and can weigh from 150 to 450 pounds. Accordingly, removing manhole covers and inspecting the contents of the internal atmosphere can be physically exhausting and dangerous, often resulting in back, leg, or arm injury.
To gain access to the interior environment, manhole covers are physically dislodged and at least partially removed from the opening to permit the entry of probes, tubes or other devices. Removing a manhole cover ordinarily requires at least two able-bodied field crew members and specialized tools such as a four to eight foot crow bar, a 10 pound hammer, a sledge hammer, and two manhole hooks. The manhole hooks are normally used to pull the panel or manhole cover from its support structure. However, oftentimes the manhole cover is stuck tightly to its structure or receiving frame due to foreign matter such as dirt, rocks, roadway tar, etc. The specialized tools are used to pry open or pound the cover and frame thereby breaking the seal caused by the foreign matter so that the cover can be successfully dislodged or removed with the manhole hooks. Upon completion of an inspection, workers must return the manhole cover to its support structure by using the manhole hooks and other tools. The repeated manhole cover manipulation, required for even minor utility system inspections, can cause severe or permanent injury to utility workers.
Utility companies, especially electric utilities, occasionally experience explosions within their structures. The explosions may be caused, for example, by electric cable failures which may short creating high energy arcing between the cable""s conductors. The arcs may decompose air, water, insulation, or other material in the structure to a flammable or explosive gaseous state. For example, decomposition products such as hydrogen, methane, acetylene, propane, etc. may combine with the underground atmosphere and/or aboveground air entering the structure to create a combustible atmosphere or mixture. As the manhole cover or panel is dislodged, air may suddenly rush into the internal atmosphere and mix with the internal gases to create a combustible gas that may come into contact with an ignition source such as the arc or other intense heat source thereby causing an explosion and/or fire (so-called xe2x80x9cbackflashxe2x80x9d). Moreover, the explosion may also start a fire within the system. The explosion and resulting fire form large amounts of dangerous toxic gases such as carbon monoxide. Because these structures may be connected to other structures through passageways or ductways, the gases may travel to adjacent utility structures and through service ducts thereby entering buildings and homes and endangering people and animals.
A utility worker or other individual who must enter a utility system is typically unaware of the contents of the internal atmosphere. Combustible or toxic gases may be present and explode without warning causing serious injury to individuals in the area. Accordingly, a need exists for a device and method for inspecting the contents of an internal atmosphere that does not require removing or dislodging a panel or manhole cover. The need also exists for increasing the accuracy of the inspection and eliminating xe2x80x9cbackflashxe2x80x9d.
Similarly, electrical connection boxes such as Electric Main Service Disconnect Switch Enclosures, found in most buildings, may contain combustible or flammable gases. In response to an emergency, an operator such as a firefighter typically operates a main electrical switch or circuit breaker that is located within such a box to disconnect the electricity to the building. However, by turning off the electric supply to the building, an operator may unknowingly produce sparks or arcing between the two internal metal contacts of the switch. This sparking or arcing occurs at the moment the contacts separate from each other due to the potential difference between the metal contacts. The resulting spark or arc may ignite combustible gases that may exist within the connection box and create a dangerous explosion that can severely injure the operator of the switch and damage surrounding equipment. As a result, the operator may be required to remove a cover, panel or door attached to the switch enclosure so that the operator can determine whether it is safe to disconnect the electricity to the building. To remove the cover, panel or door, screws may have to be removed thereby consuming valuable time in an emergency situation. Thus, a need exists for quickly and accurately analyzing the internal atmosphere of a utility system connection box without disassembling and opening its panel, door, cover, or other enclosure in a time consuming manner.
In accordance with the present invention an inspection plug is provided that can be removably or fixedly inserted into an environment-defining barrier or panel, such as a manhole cover, wall or closure of a containment system. Typically, the barrier or panel includes an opening or hole into which the inspection plug can be inserted. In illustrative embodiments, the plug provides an inspection port and a closure member for the port, the closure member being sufficiently yieldable to permit the insertion of a probe through the inspection port and returning to a closed state after the probe has been extracted. In one embodiment, the inspection plug may include a peripheral shoulder, an openable or movable cap, and a body such as a cylindrical member. The cap may be hingably attached to the shoulder and resiliently biased by normally a spring or spring-like member into a closed position to seal the cylinder opening. In yet other embodiments, the closure member may comprise a resilient insert or cap having openings through which a probe may be inserted, in which the openings automatically seal to its normally closed position when the probe is removed.
That is, the present invention provides an inspection closure assembly having a panel with an opening, an inspection plug received within the opening and extending therethrough. The plug has a plug body with a passageway extending between first and second ends thereof and terminating at the first end in a probe-receiving port. The assembly also may include a closure member, which is yieldable to a degree sufficient to admit the insertion of an object such as an inspection probe through the port, for the probe-receiving port.
The present invention also provides an inspection closure assembly receivable within a panel opening that extends through a panel. The assembly includes a plug body having a passageway extending between the first and second ends thereof and terminating at the first end in a probe-receiving port. The assembly also may include a resiliently biased cap member oriented at least partially within the probe-receiving port, the cap member being pivotally oriented about a rod-shaped member mounted in the plug body and being yieldable to a degree sufficient to admit the insertion of an object, such as an inspection probe, through the port.
The present invention also provides a method of using an inspection plug that includes a resiliently movable cap member, which is located at a port opening and may be within a passageway defined by a cylinder, for closing and opening the probe receiving port. The cap is preferably biased toward the outer surface of the panel such that inward pressure on the cap causes it to open to permit the entrance of a probe into the probe-receiving port or passageway. In addition, the inspection plug assembly may contain a gel material, wherein the cap or a part thereof is made of an elastic or flexible material and contains one or more slits. The cylindrical member contains an elastic or flexible enclosure at the bottom of the inspection plug containing one or more slits to contain and house the gel material.
The present invention also provides a method of assembling a panel with an inspection plug having first and second surfaces and an opening extending therethrough. The method includes providing an inspection plug having a plug body defining therein a passageway extending between the ends thereof and terminating at one of the ends in a probe-receiving port, and having a resiliently movable closure member located within the passageway for closing and opening the probe receiving port. The method may additionally include inserting a portion of either of the ends of the body into the panel opening, and securing the plug in the panel opening.
The present invention also provides a method of employing an inspection plug having a plug body with a first end, a second end and defining therein a passageway extending between the ends and terminating at the first end in a probe receiving port. The inspection plug also may include a resiliently movable cap member located at least partially within the passageway for closing and opening the probe receiving port. The method includes operating the cap to permit the entrance of a probe into the probe receiving port, and inserting the probe into the passageway of the inspection plug.
The plug and cap assembly can be threaded at one extreme to allow attachment to the panel by a lock washer and nut. Alternatively, attachment may be by flexible locking prongs, a locking mechanism, rivet, friction, etc.
The present invention also provides for the ability to quickly and easily inspect the contents within the structure by visual means such as with a camera/video system and thus not have the burden to removing or dislodging a heavy cover using cumbersome tools.
The present invention also provides a method for inspecting an internal atmosphere using an inspection plug for accessing the internal atmosphere.
The present invention also provides an inspection plug and alarm combination and a method for using same.